Gem Notes

Jewelry Designs Transform Nature

Working with “alternative” or ornamental gemstones allows a California designer to transport nature into the highly artificial world of jewelry fashion.

Craig Marinovich, CEO of Gem Shapes in Sausalito, uses materials like fossilized dinosaur bone, mammoth ivory, boulder opal, bloodstone, and gold, copper, and silver embedded in quartz to project colors and geographical features prevalent in the natural world. “Within these gems,” says Marinovich, “are reflecting rivers, sunburnt deserts, brilliant marshes, starry skies and galaxies, rocky coasts, and undulating seas.” Marinovich transforms these visions into jewelry with designs that enhance each gem’s unique qualities.

The classic gold in quartz is a good example of an ornamental stone’s ability to seize the imagination. As you see the gold veining branch out into the white quartz, you get an overwhelming desire to go digging for gold yourself.

The premium-quality gems are those with the purest of gold, showing the “buttery look” of 22k and above, veined in pure white opaque quartz. The lower-quality gold in quartz is recognizable by its gray quartz, impurities, and poor design of gold veining. Yet there are many who prize these supposedly inferior characteristics.

Most of the prime material is gathered from private collectors and small mines. The difficulty in selecting the right piece is not knowing beforehand how much of the gold veining will be lost during polishing. With rough diamonds, the worry is weight loss. With gold in quartz (copper and silver, too) the worry is losing the vein. You can’t judge whether the vein is thick enough to be polished down even a millimeter in depth. Sometimes the polishing may increase or widen the veining.

This uncertainty adds to the excitement in working with these materials. There’s no guarantee what you’ll get. “Everything we use is a window view of the physical world around us,” says Marinovich. Take Mayan Skystone, another unusual material he works with. Chrysocolla (a light greenish blue mass), cuprite (dark red crystals of 3.5 to 4 in hardness) and shattuckite twist their way through each other, looking like an aerial painting of the Yucatan complete with land- and seascape.

One of the rarest materials Marinovich uses is Star of Alaska. His only supply comes from a private collector who obtained it 30 years ago. Found in North America, Star of Alaska is basically covellite (indigo blue iridescent crystals of 1.5-2.0 hardness). It also contains copper sulfide, which is sometimes associated with chalcopyrite (brassy yellow crystals with iridescent tarnish and a hardness of 3.5-4.0) and chalcocite (2.5-3.0 in hardness).

Marinovich also likes crystalline silver – silver in marble – with its veins and dendrites. He compares it to “a lightning storm through a winter sky.” This unusual combination can occur with two metallic minerals, nickelite (pinkish-bronze mass of 5.0-5.5 in hardness) and cobaltite (violet to purplish-gray). Marinovich bought his crystalline silver from a private collector. It was found more than 100 years ago, and no more has been mined since then.

Copper in quartz, from the mines of Arizona, is somewhat more earthy than the gold in quartz. The quartz here is almost always gray. Alongside the native copper is a red cuprite and other assorted minor minerals. Copper forms in more “wires” than veins, which makes the observed pattern even more difficult to retain during polishing. When first polished, the copper appears as a bright and shiny penny. And just like the coin, it soon oxidizes to the dull and dark side we are familiar with. But the “oxidation is okay,” says Marinovich. “It just reflects life, with things changing in a normal way.”

Of course, life as we know it does not include the dinosaur, but jewelry can. Dinosaur bone is another of the earthy materials Gem Shapes uses in its Coeur de Lion line of men’s jewelry. The fossilized bone was obtained legally from collectors before antiquities were regulated. The better-quality bone is dark red, with dark brown veining – a spider web look. There are also pink and salmon colors, with a few light blue pieces (very rare).

One interesting note about all these softer gems is that they respond well to the use of epoxies and other hardening agents. Marinovich thinks “increasing the jewelry’s durability and wearability” is important because he expects his items to be handed down from generation to generation. “If we can enhance it, we will,” he says, adding that he always informs his customers of the process.

TIFFANY GIVES BOOST TO NEW AGTA LAB

The American Gem Trade Association’s new colored gem lab in New York got a big boost from Tiffany & Co., which made a $150,000 grant to the new venture and promised to send a “significant number” of its colored gemstones there for grading.

The AGTA board already has pledged $250,000 to get the lab started. It also has received financial support from a number of the association’s individual members.

Douglas Hucker, AGTA’s executive director, said Tiffany’s commitment to use the new lab as a source for gemstone reports will give the project a “wonderful” initial boost. He added that many dealers already have promised to use the facility.

A lease for the lab’s New York home is expected to be signed very shortly. The lab should be “up and going” by late August, Hucker said, and will be open to anyone in the industry, domestic or foreign.

He explained that the lab’s colored gemstone reports will provide detail on color, enhancements, and, by request, country of origin. However, he said, one of the major thrusts will be in research. Ken Scarratt, the director of the new lab, already has hired two graders who worked with him at the Asian Institute of Gemological Science (AIGS) in Bangkok. Scarratt, who left AIGS earlier this year, currently is acquiring the testing equipment the venture needs to get started.

AGTA is now recruiting a board to oversee lab operations. Hucker said it will be made up of a cross section of the industry and will include retail jewelers, mass merchants, educators, appraisers, and a consumer advocate along with AGTA representatives.

FIND IN ARKANSAS NETS FLAWLESS GEM

A 3-ct. diamond found by a freelance stone scavenger eight years ago at the Crater of Diamonds State Park in Arkansas has been turned into a 1.09-ct. gem valued at $33,000.

Since 1972, the public has been permitted to search for stones at the park, which sits atop one of the two diamond mines in the United States (the other is in Colorado). Shirley Strawn, 41, a park regular, unearthed the stone after searching the park every day for a year. “It was so white and pretty that I knew in my heart that it would be good,” she says.

On a friend’s recommendation, she took it to Bill Underwood of Underwood’s Jewelers in Fayetteville, a former president of the American Gem Society. He suggested that it be sent to Lazare Kaplan for cutting, and then to the American Gem Society lab in Las Vegas. The lab graded it “Ideal Cut D-Flawless,” or 0-0-0 in AGS terms.

“It is rare for a diamond like that to come even from Africa,” Underwood says. “But for it to come from what is basically an unproductive mine – where they are just digging around in the top four or five feet – is just amazing.”

Strawn has named her big find the Strawn/Wagner Diamond, after herself and her grandfather, who worked at Crater Park. She plans to sell it at Underwood’s in a few months. Initial offers already have topped the $33,000 appraised value, according to Underwood.

Also recently at Crater Park, a mother and daughter unearthed a 7.28-ct. yellow diamond. The duo are deciding whether to leave the stone, described as “gem quality,” in its rough form.

JULY’S BIRTHSTONE: THE REGAL RUBY

Ruby has long been recognized as a valuable gem. In Sanskrit, the ancient classical language of India and Hinduism, it is described as Ratmaraj, the “king of precious stones.” It was prized for its beauty while other gemstones were being ground up for use as medicines or worn to ward off evil. Ruby is noted in the Old Testament as one of the original gems in the breastplate of the high priest.

Most rubies come from Southeast Asia and Africa; the best are from Burma. In fact, Burmese rubies have been traded and fought over for centuries. One of the more intriguing historical rubies is the Prince’s Ruby, on display at the Bowers Museum of Cultural Art in Santa Ana, Calif. It is said to have belonged to the Shah Jahan (1592-1666), builder of the Taj Mahal. The gem, weighing in at an astounding 174.67 cts., is engraved with calligraphy from the Koran.

Because ruby was the first described red gemstone, its name has been attached to many other minerals with a ruddy hue. Red tourmaline, for example, has been termed rubelite, red spinel is known as ruby spinel, red opal is called rubolite, yellow orange spinel is rubicelle, and a red stained quartz has been given the moniker rubace.

It wasn’t until more recent mineralogical times that the ruby became known as the red variety of corundum, the family name for sapphires. The only thing separating ruby from sapphire is its color.

Localities. Fine, gem-quality natural rubies come from many areas. The color of Burmese rubies, described as “pigeon blood,” is the most sought after. Some Burmese rubies, though, aren’t representative of that top-color quality. Gems from Mong Hsu, a relatively new deposit in Burma, show the fine Burma color, but that’s usually attained through heat treatment of the rough.

Thai, Vietnamese, and Cambodian ruby mines are located in mountain ranges similar to Burma’s, so it’s not unusual to find similar qualities among gems from these areas. Inclusions specific to local mines can help the gemologist or mineralogist identify the country of origin.

Sri Lanka, Afghanistan, Tanzania, Kenya, and Madagascar also have significant ruby deposits. Only within the past few decades have the African countries and Afghanistan produced fine-quality rubies.

Color. Color ultimately determines whether a gem is called a sapphire or a ruby. By definition, a ruby must be predominantly red. Red, purplish-red, and orangy red are its common hues. If a stone is more purple than red, it’s a purple sapphire; if it’s more orange than red, it’s an orange sapphire.

If the gem is more pink than red, I call it a pink sapphire, but others, primarily in Southeast Asia, will classify it as a pink ruby. Their justification is that pink is a red of desaturation.

Lighting is a key element in distinguishing ruby or sapphire. Reddish gems appear even more so under incandescent lights. The temperature of fluorescent light fixtures can also affect the gem in the same manner. Lights with a temperature of 6,500 degrees Kelvin enhance blue or green in gems, while fluorescent lights at 5,500 degrees Kelvin enhance yellow and red wavelengths. There are no current international standard lighting temperatures for color grading gemstones.

Synthetic rubies. Probably the most difficult gemological determination for ruby is identifying whether the gem is natural or synthetic. With the advent of laboratory-produced rubies such as Ramaura and Chatham flux synthetics and Durous, hydrothermal, and Czecralski pulled synthetics, the task is daunting. Gems and Gemology magazine has by far the most in-depth studies for each of these processes and the determining factors for each. As they say in gemology class, “when in doubt, send it out.” If you can’t tell what it is, send it to the Gemological Institute of America Gem Trade Lab for a proper identification.

Enhancement. Many natural rubies are enhanced. Heat treatment is quite common, especially in Thailand. Borax powder is used to surround the gem as a protective medium during heat treatment. An additional enhancement occurs when the borax melts under high temperature to become a glass. This glass can then flow into fractures and cavities. The fillings improve the gems’ face-up appearance and can add deceptive weight.

Diffusion treatment, a less common type of enhancement, starts with sapphires or rubies of inferior color and introduces color into the surface layer of the gem, giving it a much better appearance. You can remove diffusion treatment only by repolishing the surface layer where the color has been added.

One of the oldest methods of ruby enhancement is the addition of dye in fractures. Adding red dye to white opaque fractures helps the face-up appearance of lower-quality gems. It is considered unethical to enhance ruby with red dye, glass filling, or diffusion without disclosure.

Prices. For fine-quality 1-ct. to 2-ct. rubies, the wholesale cost can vary from $2,000 to $3,000 per carat. If the ruby is determined to be from Burma, the estimated value could increase because of the popularity and history behind the Burmese name and legend.

Birthstone alternative. The alternative birthstone for July is onyx, the black-and-white striped chalcedony. It is a relatively common opaque quartz material used mainly in men’s and cameo/intaglio jewelry and can be a terrific option for those who wish to wear something a little more unusual.

Astrological gems. If you were born between July 1 and July 20, your astrological sign, Gemini, is represented by the agate. From July 21 through August 20, your sign is Leo, represented by the onyx.